Facebook failed to enforce its own rules to curb an oil and gas industry misinformation campaign over the climate crisis during last year’s presidential election, according to a new analysis released on Thursday.

The report, by the London-based thinktank InfluenceMap, identified an increase in advertising on the social media site by ExxonMobil and other fossil-fuel companies aimed at shaping the political debate about policies to address global heating.

InfluenceMap said its research shows the fossil-fuel industry has moved away from outright denying the climate crisis, and is now using social media to promote oil and gas as part of the solution. The report also exposed what it said was Facebook’s role in facilitating the dissemination of false claims about global heating by failing to consistently apply its own policies to stop erroneous advertising.

“Despite Facebook’s public support for climate action, it continues to allow its platform to be used to spread fossil-fuel propaganda,” the report said. “Not only is Facebook inadequately enforcing its existing advertising policies, it’s clear that these policies are not keeping pace with the critical need for urgent climate action.”

The report found that 25 oil and gas industry organisations spent at least $9.5m to place more than 25,000 ads on Facebook’s US platforms last year, which were viewed more than 431m times. Exxon alone spent $5m.

“The industry is using a range of messaging tactics that are far more nuanced than outright statements of climate denial. Some of the most significant tactics found included tying the use of oil and gas to maintaining a high quality of life, promoting fossil gas as green, and publicizing the voluntary actions taken by the industry on climate change,” the report said.

The report noted a rise in spending on Facebook ads in July 2020, immediately after then-presidential candidate Joe Biden announced a $2tn climate plan to promote the use of clean energy. The spending remained high until after the election four months later.

“This suggests the oil and gas industry uses Facebook advertising strategically and for politically motivated purposes,” the report said.

InfluenceMap said it found 6,782 energy industry ads on Facebook last year promoting claims that natural gas is a green or low carbon fuel, even though research by the Intergovernmental Panel on Climate Change says otherwise.

The research found that Exxon in particular used the social media site to push continued use of oil as affordable, reliable and important to keep the US from relying on other countries for its energy supply.

InfluenceMap also accused the company of running misleading ads that sought to shift the greater responsibility for cutting carbon emissions from industry to the lifestyle choices of ordinary Americans. The report said that the International Energy Agency calculates that global targets to reduce emissions rely heavily on the energy industry moving to green technologies, while just 8% of reductions will come from consumer choices such as taking fewer flights.

“These messages are often packaged in adverts promoting the climate-friendliness of oil and gas companies and the necessity of oil and gas for maintaining a high quality of life,” the report said.

InfluenceMap also drew attention to the part played by industry-funded groups led by the American Petroleum Institute, which spent $3m on Facebook ads last year portraying fossil-fuel companies as climate-friendly.

InfluenceMap said that while Facebook removed some ads for making false claims or failing to include a disclaimer identifying them as about environmental politics, it permitted many others to go unchallenged.

Facebook told the Guardian it has taken action against some groups running pro- fossil-fuel ads and that multiple advertisements have been rejected because they were run without being identified as political.

“We reject ads when one of our independent factchecking partners rates them as false or misleading, and take action against pages, groups, accounts, and websites that repeatedly share content rated as false,” said a Facebook spokesperson.

Last year, a group of US senators wrote to Mark Zuckerberg, Facebook’s chief executive, about concerns that the social media platform was permitting demonstrably false claims about the climate crisis to be posted on the grounds they were ‘opinion’.

“Given Facebook’s long and troubling history with disinformation, it is deeply concerning that Facebook has now determined that climate disinformation is reportedly “immune to fact-checking”, said the senators, including Elizabeth Warren.

“The climate crisis is too important to allow blatant lies to spread on social media without consequence.”